Fused filament fabrication using multi-segment filament

ABSTRACT

A thermoplastic filament adapted for use in a fused filament fabrication (FFF) printer which has a plurality of segments wherein each pair of adjacent segments is compositionally different and is arranged in a specific order. Also, a method for printing a three-dimensional (3D) article by printing such a filament in a fused filament fabrication (FFF) printer, wherein the fused filament fabrication (FFF) printer carries out a pattern of printing synchronized with the order of the segments in such a filament. Further, a method and device for fabricating such thermoplastic filaments.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application makes reference to and claims the priority benefit ofU.S. Provisional Application No. 61/928,573, filed Jan. 17, 2014,entitled “Fused Filament Fabrication with Multi-Material Filament,” theentire disclosure and contents of which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to thermoplastic filament adapted for usein a fused filament fabrication (FFF) printer which has a plurality ofsegments wherein each pair of adjacent segments having at least onedifferent feature and is arranged in a specific order. The presentinvention also relates to a method for creating a three-dimensional (3D)article by printing such a thermoplastic filament in a fused filamentfabrication (FFF) printer, wherein the fused filament fabrication (FFF)printer carries out a pattern of printing synchronized with the order ofthe segments in such a filament. The present invention further relatesto a method and device for fabricating such thermoplastic filaments.

BACKGROUND

Additive manufacturing (also commonly referred to as three-dimensional(3D) printing) may create physical objects, structures, etc., based upona computer-controlled program which instructs the 3D printer how todeposit successive layers of extruded material which may then fusetogether to form the printed article, device, component, object,structure, part, etc. Fused deposition modeling (FDM), also referred toherein as fused filament fabrication (FFF), is one such additivemanufacturing process. In fused filament fabrication (FFF), athermoplastic filament may be supplied from a coil of such filament toan extrusion nozzle. In many FFF machines, a worm-drive gear systemengages and pushes the filament into and through the nozzle at acontrolled rate. The nozzle may be heated to melt the filament with themelted filament then being deposited by an extrusion head as beads ofmaterial which may then rapidly harden after extrusion from the nozzle.

While depositing the melted filament, the nozzle may be moved in bothhorizontal and vertical directions by a numerically (e.g., computer)controlled mechanism. For example, the positioning of the nozzle mayfollow a build path controlled by a computer-aided manufacturing (CAM)software program. The build path defines the pattern for how the meltedfilament is deposited from the extrusion head as “road(s)” of materialto form a given layer. Accordingly, in FFF additive manufacturing, thearticle, device, component, object, structure, part, etc., to beproduced is thus built from the bottom up, layer by layer.

SUMMARY

In a first broad aspect of the present invention, there is provided anarticle comprising a thermoplastic filament adapted for a fused filamentfabrication (FFF) printer, the filament comprising:

-   -   a plurality of segments, each of the segments comprising a        thermoplastic polymer;    -   each pair of adjacent segments having at least one different        feature;    -   wherein the segments are arranged in a specified order in the        filament to provide a synchronized pattern of printing when the        filament is printed with a fused filament fabrication (FFF)        printer.

In a second broad aspect of the present invention, there is provided amethod for printing a three-dimensional (3D) article, which comprisesthe following steps of:

-   -   (a) providing a thermoplastic filament adapted for a fused        filament fabrication (FFF) printer, the filament comprising:        -   a plurality of segments, each of the segments comprising a            thermoplastic polymer;        -   each pair of adjacent segments having at least one different            feature;        -   wherein the segments are arranged in a specified order in            the filament; and    -   (b) printing the filament of step (a) with a fused filament        fabrication (FFF) printer to form the three-dimensional (3D)        article, wherein the fused filament fabrication (FFF) printer        carries out a pattern of printing synchronized with the order of        the segments in the filament.

In a third broad aspect of the present invention, there is provided amethod for preparing a thermoplastic filament adapted for a fusedfilament fabrication (FFF) printer, which comprises the following stepsof:

-   -   (a) providing a plurality of segments, each of the segments        comprising a thermoplastic polymer and having a pair of spaced        apart ends, the segments being arranged in a specified order        such that adjacent segments have at least one different feature;        and    -   (b) joining the ends of the adjacent segments of step (a) to        form a thermoplastic filament having a plurality of segments        which provides a synchronized pattern of printing when the        filament is printed with a fused filament fabrication (FFF)        printer.

In a fourth broad aspect of the present invention, there is provided adevice for fabricating a continuous thermoplastic filament having aplurality of segments, which comprises:

-   -   a first filament supply component for supplying a first        thermoplastic filament;    -   a second filament supply component for supplying a second        thermoplastic filament;    -   a filament cutting component for cutting each of the first and        second filaments into segments, each of the segments having a        forward end and trailing end spaced apart from the forward end;    -   a first filament guide component for guiding the first filament        into position to be cut by the filament cutting component;    -   a second filament guide component for guiding the second        filament into position to be cut by the filament cutting        component;    -   a filament segment joining section positioned after the filament        cutting component, the filament joining section having:        -   a chamber for guiding and aligning the forward end of one            segment of the first and second filaments into contact with            the trailing end of the other segment of the first and            second filaments; and        -   a heater element for heating and joining the trailing end to            the forward end when in contact to form a continuous            thermoplastic filament having a plurality of segments;    -   wherein the first and second filament guide components are        movable so as to alternatively and sequentially permit the first        and second filaments to be cut by the filament cutting        component.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view illustrating an embodiment of athermoplastic filament of the present invention;

FIG. 2 is a side-sectional view illustrating an embodiment of fusedfilament fabrication (FFF) printing according to the present inventionwith a thermoplastic filament such as shown in FIG. 1;

FIG. 3 is a perspective view illustrating a pattern of printing with afused filament fabrication (FFF) printer using a thermoplastic filamentsuch as shown in FIG. 1; and

FIG. 4 is a schematic illustration of an embodiment of a filamentfabrication device for fabricating a thermoplastic filament such asshown in FIG. 1.

DETAILED DESCRIPTION

It is advantageous to define several terms before describing theinvention. It should be appreciated that the following definitions areused throughout this application.

DEFINITIONS

Where the definition of terms departs from the commonly used meaning ofthe term, applicant intends to utilize the definitions provided below,unless specifically indicated.

For the purposes of the present invention, directional terms such as“outer,” “inner,” “upper,” “lower,” “top,” “bottom,” “side,” “front,”“frontal,” “forward,” “rear,” “rearward,” “back,” “trailing,” “above,”“below,” “left,” “right,” “horizontal,” “vertical,” “upward,”“downward,” etc. are merely used for convenience in describing thevarious embodiments of the present invention. For example, theembodiments of the present invention illustrated in FIGS. 1 through 4may be oriented in various ways.

For the purposes of the present invention, the term “thermoplastic”refers to the conventional meaning of thermoplastic, i.e., acomposition, compound, material, etc., that exhibits the property of amaterial, such as a high polymer, that softens or melts so as to becomepliable, malleable, etc., when exposed to sufficient heat and generallyreturns to its original condition when cooled to room temperature.

For the purposes of the present invention, the term “filament” refers toa continuous length of material which has a thread-like structure, i.e.,having a length which greatly exceeds its diameter, and which may beused with fused filament fabrication (FFF) printer. A filament may besolid or may be fluid, i.e., when liquefied, molten, melted, softened,etc.

For the purposes of the present invention, the term “segment” refers toa section, portion, region, etc., of a filament which has at least onefeature which is different from an adjacent section, portion, region,etc., of the filament

For the purposes of the present invention, the term “adjacent segment”refers to a pair of segments in a filament which are next to each other,and which, when joined, connected, fused, spliced, adhered, etc.,together, share a common end, boundary, edge, etc.

For the purposes of the present invention, the term “different feature”with respect to adjacent segments of a filament refers to differences inone or more of: the composition of the adjacent segments; the appearanceof the adjacent segments; the functional properties of the adjacentsegments, etc. Differences in composition may include one or more of:different materials, compounds, substances, etc., present in theadjacent segments; different amounts of the same materials, compounds,substances, etc., present in the adjacent segments, etc. Differences inappearance may include one or more of: differences in color, shape,opacity, transparency, translucency, fluorescence, etc., of the adjacentsegments. Differences in functional properties may include one or moreof: differences in physical, structural, mechanical, chemical,electrical, etc., properties of the adjacent segments, such as, forexample, differences in electrical conductivity, thermal conductivity,mechanical strength, viscoelasticity, solubility, magneticsusceptibility, etc.;

For the purposes of the present invention, the term “polymer” refers tothose polymers which are thermoplastic. Suitable thermoplastic polymersfor use herein may include, for example, one or more of: acrylate ormethylmethacrylate polymers or copolymers, such as polyacrylates,polymethylmethacrylates, etc.; polylactic acid (PLA) polymers;polyhydroxyalkanoate (PHA) polymers, such as polyhydroxybutyrate (PHB);polycaprolactone (PCL) polymers; polyglycolic acid polymers;acrylonitrile-butadiene-styrene polymers (ABS); polyvinylidene fluoridepolymers, polyurethane polymers, polyolefin polymers (e.g.,polyethylene, polypropylene, etc.), polyester polymers, polyalkyleneoxide polymers, such as polyethylene oxide (PEO), polyvinyl alcohol(PVA) polymers, polyamide polymers, polycarbonate polymers, high impactpolystyrene (HIPS) polymers, polyurethane polymers, etc. These polymersmay be used in pure form or as a blend with each other or otheradditives such as plasticizers, fillers, solvents, colorants, etc., maybe water-soluble (e.g., water-soluble polyethylene oxide (PEO)polymers), etc.

For the purposes of the present invention, the term “polymer matrix”refers to a matrix which provides the external or continuous (bulk)phase in which may be dispersed one or more other compounds, materials,substances, etc., and which, besides the dispersed one or more othercompounds materials, substances, etc., may comprise one or morepolymers, as well as one or more other optional additives, such asfillers, plasticizers, solvents, colorants, etc.

For the purposes of the present invention, the term “carbon material”material refers to materials made of carbon. Carbon materials mayinclude one or more of: graphite; graphite flakes; carbon black;graphene; graphene-like materials; (e.g., reduced graphene oxide,functionalized graphene, graphene oxide, partially reduced grapheneoxide, etc.); carbon-based nanofibers; carbon-based nanotubes; etc.

For the purposes of the present invention, the term “graphene-likematerial” refers to a material, substance, etc., which may have alayered structure the same or similar to graphene. Graphene-likematerials may include one or more of: graphene; functionalized graphene;graphene oxide; partially reduced graphene oxide; graphite flakes;molybdenum disulfide (MoS₂); molybdenum diselenide (MoSe₂); molybdenumditelluride (MoTe₂); tungsten disulfide (WS₂); tungsten diselenide(WSe₂); hexagonal boron nitride (h-BN); gallium sulfide (GaS); galliumselenide (GaSe); lanthanum cuprate (La₂CuO₄); bismuth tritelluride(Bi₂Te₃); bismuth triselenide (Bi₂Se₃); antimony triselenide (Sb₂Se₃);zinc oxide (ZnO); niobium disulfide (NbS₂); niobium diselenide (NbSe₂);tantalum disulfide (TaS₂); vanadium disulfide (VS₂); rhenium disulfide(ReS₂); rhenium diselenide (ReSe₂); titanium disulfide (TS₂); titaniumdiselenide (TSe₂); indium trisulfide (InS₃); zirconium disulfide (ZrS₂);zirconium diselenide (ZrS₂); cadmium selenide (CdSe); etc.

For the purposes of the present invention, the term “graphene” refers topure or relatively pure carbon in the form of a relatively thin, nearlytransparent sheet, which is one atom in thickness (i.e., a monolayersheet of carbon), or comprising multiple layers (multilayer carbonsheets), having a plurality of interconnected hexagonal cells of carbonatoms which form a honeycomb like crystalline lattice structure. Inaddition to hexagonal cells, pentagonal and heptagonal cells (defects),versus hexagonal cells, may also be present in this crystal lattice.

For the purposes of the present invention, the term “functionalizedgraphene” refers to graphene which has incorporated into the graphenelattice a variety chemical functional groups such as —OH, —COOH, NH₂,etc., in order to modify the properties of graphene.

For the purposes of the present invention, the term “graphene oxide”(also known as “graphitic acid” and “graphite oxide”) refersinterchangeably to a compound of carbon, oxygen, and hydrogen which mayexist in variable ratios of these three atoms, and which may be obtainedby treating graphite with strong oxidizers.

For the purposes of the present invention, the term “partially reducedgraphene oxide” refers to graphene oxide that, upon reduction, containsfrom about 5 about 30% oxygen by weight of the graphene oxide.

For the purposes of the present invention, the terms “grapheneplatelets” and “graphene sheets” refer interchangeably to platelets ofgraphene comprising one or more layers of a two-dimensional (2D)graphene plane, and may also refer to platelets and sheets comprised ofgraphene oxide, partially reduced graphene oxide, functionalizedgraphene, etc.

For the purposes of the present invention, the term “graphenenanoplatelets (NGPs)” and “nanosheets” refer interchangeably toplatelets of graphene, and may also refer to platelets and sheetscomprised of graphene oxide, partially reduced graphene oxide,functionalized graphene, etc., having a thickness in the range of fromabout 0.34 to about 100 nm.

For the purposes of the present invention, the term “graphene-likenanoplatelets” refers to graphene-like materials having plateletcharacteristics the same or similar to graphene nanoplatelets (NGPs).

For the purposes of the present invention, the term “flakes” refers toparticles in which two of the dimensions (i.e., width and length) aresignificantly greater compared to the third dimension (i.e., thickness).

For the purposes of the present invention, the term “nanoscopic” refersto materials, substances, structures, etc., having a size in at leastone dimension (e.g., thickness) of from about 1 to about 1000nanometers, such as from about 1 to about 100 nanometers. Nanoscopicmaterials, substances, structures, etc., may include, for example,nanoplatelets, nanotubes, nanowhiskers, etc.

For the purposes of the present invention, the term “quantum dot” refersto a nanocrystal made from graphene or graphene-like materials which aresmall enough to exhibit quantum mechanical properties.

For the purposes of the present invention, the term “liquid” refers to anon-gaseous fluid composition, compound, substance, material, etc.,which may be readily flowable at the temperature of use (e.g., roomtemperature) with little or no tendency to disperse and with arelatively high compressibility.

For the purposes of the present invention, the term “room temperature”refers to refers to the commonly accepted meaning of room temperature,i.e., an ambient temperature of from about 20° to about 25° C.

For the purposes of the present invention, the term “extrudable” refersto composition, compound, substance, material, etc., which issufficiently malleable, pliable, thermoplastic, etc., such that it maybe forced through an extrusion orifice or die.

For the purposes of the present invention, the term “fusible” refers toa thermoplastic composition, substance, material, etc., which may befused, sintered, joined together, combined, etc., by the application ofheat.

For the purposes of the present invention, the term “three-dimensional(3D) printable material” refers to a thermoplastic composition,substance, material, etc., which may be formed into a three-dimensional(3D) article, device, component, object, structure, part, etc., by athree-dimensional (3D) printing technique

For the purposes of the present invention, the term “three-dimensional(3D) printing” (also known as “additive printing” and “additivemanufacturing”) refers to any of various processes, techniques, etc.(e.g., coating, spraying, depositing, applying, extruding, fusing,sintering, etc., or any combination thereof) for making athree-dimensional (3D) article, device, object, component structure,part, etc., from a three-dimensional (3D) model, other electronic datasource (e.g., computer assisted drawing (CAD) program file,stereolithographic (STL) file, etc.), etc., through additive processesin which successive layers of material (e.g., filaments, films, powders,particles, pellets, etc.) may be laid down, for example, under computercontrol. Three-dimensional (3D) printing processes, techniques, etc.,may include, for example, fused filament fabrication (FFF), selectivelaser sintering (SLS) (also referred to herein interchangeably asselective laser melting (SLM)), inkjet head 3D printing (also referredto herein interchangeably as inkjet 3D printing), etc.

For the purposes of the present invention, the term “fused filamentfabrication (FFF) (also referred to herein interchangeably as fuseddeposition modeling (FDM), fused extrusion deposition (FED), or PlasticJet Printing (PJP))” refers to a three-dimensional (3D) printingtechnique wherein a thermoplastic filament (preformed or formed in situ)is extruded from an extrusion (printing) nozzle (also referred tointerchangeably as a “printing head”) in layers which, due to beingliquefied, molten, softened, melted, etc., adhere (fuse) together toform the three-dimensional (3D) article, device, component, object,structure, part, etc.

For the purposes of the present invention, the term “fused filamentfabrication (FFF) printer” refers to any three-dimensional (3D) printerwhich operates by using a fused filament fabrication (FFF) technique.

For the purposes of the present invention, the term “road” refers to acontinuous length of liquefied, molten, melted or softened materialwhich is laid down after extrusion of the thermoplastic filament from afused filament fabrication (FFF) printer.

For the purposes of the present invention, the term “colorants” refersto additive compositions, compounds, substances, materials, etc., suchas pigments, tints, etc., which impart color to a filament or a segmentof a filament.

For the purposes of the present invention, the term “fillers” refers toadditives which may alter a composition's mechanical properties,physical properties, chemical properties, appearance, etc, and which mayinclude, for example, one or more of: magnesium oxide, hydrous magnesiumsilicate, aluminum oxides, silicon oxides, titanium oxides, calciumcarbonate, clay, chalk, boron nitride, limestone, diatomaceous earth,mica, glass quartz, ceramic and/or glass microbeads, metal or metaloxide fibers and particles, Magnetite®, magnetic iron(III) oxide, carbonnanotubes and/or fibers, wood, cements, adhesives, gems, decorativeelements, etc.

For the purposes of the present invention, “plasticizer” refers to theconventional meaning of this term as an additive which, for example,softens, makes more flexible, malleable, pliable, plastic, etc., apolymer, thus providing flexibility, pliability, durability, etc., whichmay also decrease the melting and the glass transition temperature ofthe polymer, and which may include, for example, one or more of:tributyl citrate, acetyl tributyl citrate, diethyl phthalate, glyceroltriacetate, glycerol tripropionate, triethyl citrate, acetyl triethylcitrate, phosphate esters (e.g., triphenyl phosphate, resorcinolbis(diphenyl phosphate), olicomeric phosphate, etc.), long chain fattyacid esters, aromatic sulfonamides, hydrocarbon processing oil,propylene glycol, epoxy-functionalized propylene glycol, polyethyleneglycol, polypropylene glycol, partial fatty acid ester (Loxiol GMS 95),glucose monoester (Dehydrat VPA 1726), epoxidized soybean oil,acetylated coconut oil, linseed oil, epoxidized linseed oil, etc.

For the purposes of the present invention, the term “solvent” refers toa liquid which may dissolve or suspend another material which may be asolid, gas, or liquid. Suitable for use as additives may include one ormore of: water, acetone, chloroform, dichloromethane, etc.

For the purposes of the present invention, the term “blend,” “blending,”and similar words and/or phrases refers to combining, mixing together,unifying, etc., a plurality of components, compounds, compositions,substances, materials, etc.

For the purposes of the present invention, the term “substantiallyuniform” refers to a dispersion, material, substance, etc., which issubstantially uniform in terms of composition, texture, characteristics,properties, etc.

For the purposes of the present invention, the term “heat sink refers toa passive heat exchanger which cools a device by dissipating heat intothe surrounding medium and which may be capable of efficient transferand dissipation of heat produced by other components (e.g., electronic,etc.).

For the purposes of the present invention, the term “3D currentconductors” refers to three-dimensional (3D) structures designed toconduct electrical current.

For the purposes of the present invention, the term “solar cell gridcollectors” refers to the part of the solar cell, such as is made ofmetal or other conductive material, and which collects charges generatedin/by semiconductor part of a solar cell.

For the purposes of the present invention, the term “smart labels”refers to radiofrequency identification (RFID) labels which, forexample, may be embedded as inlays inside label material, and then, forexample, printing bar code and/or other visible information on thesurface of the label.

For the purposes of the present invention, the term “radio-frequencyidentification (RFID) tags” refers to tags attached to objects thatcontain electronically stored information, and which, through use ofradiofrequency electromagnetic fields, permit automatic identifying andtracking of such tags.

For the purposes of the present invention, the term “electromagneticinterference (EMI) shielding” refers to shielding againstelectromagnetic disturbances, such as radiofrequency interference.

For the purposes of the present invention, the term “comprising” meansvarious compounds, components, ingredients, substances, materials,layers, steps, etc., may be conjointly employed in embodiments of thepresent invention. Accordingly, the term “comprising” encompasses themore restrictive terms “consisting essentially of” and “consisting of.”

For the purposes of the present invention, the terms “a” and “an” andsimilar phrases are to be interpreted as “at least one” and “one ormore.” References to “an” embodiment in this disclosure are notnecessarily to the same embodiment.

For the purposes of the present invention, the term “and/or” means thatone or more of the various compositions, compounds, ingredients,components, elements, capabilities, steps, etc., may be employed inembodiments of the present invention.

DESCRIPTION

One of the potential limitations of fused filament fabrication (FFF)printing is having the fused filament fabrication (FFF) printerincorporate different materials into the article, device, component,object, structure, part, etc., being printed. For example, the body ofthe article, device, component, object, structure, part, etc., beingcreated may have a body comprising a thermoplastic polymer matrix inwhich is embedded functional components such electronic circuitry. Butmany fused filament fabrication (FFF) printers have only one printingnozzle and thus may be limited to laying down a “road” of materialcomprising single, uniform composition. One alternative techniqueintegrating such conductive or other functioning regions, portions,sections, etc., into three-dimensional (3D) printed articles, devices,components, objects, structures, parts, etc., is to combinethree-dimensional (3D) printing, such as fused filament fabrication(FFF) printing, with direct two-dimensional (2D) printing. One suchexample is to used a heated syringe which disperses conductive traces ofa conductive material over the three-dimensionally (3D) printedcomponent. Alternatively, conductive spray-on coatings may be applied tothe three-dimensionally (3D) printed component. But these combinedmethods are still confined to printing three-dimensional (2D)electronics within the three-dimensional (3D) component, and may not beapplicable to embedding such electronics into the three-dimensional (3D)article, device, component, object, structure, part, etc.

To permit printing with more than one material, fused filamentfabrication (FFF) printers may be provided with more than one printingnozzle, with each nozzle being able to print filaments which comprisedifferent materials. For example, U.S. Pat. No. 8,827,684 (Schumacher etal.), issued Sep. 9, 2014 discloses a fused filament fabrication (FFF)printer provided with a print head unit which may have four print heads(printer nozzles) which share a common heating block and heating blocktemperature sensor(s). Each print head is provided with a separatethermoplastic filament which is controlled and driven to the print tip.Accordingly, the print heads may print different materials, e.g.,materials having different colors, to provide the printed article,device, component, object, structure, part, etc. For example, whenmultiple colors are used, all colors may be printed to fill the interiorof the printed article, device, component, object, structure, part, etc,while particular colors may be printed to color the exterior surface ofthe article, device, component, object, structure, part, etc. But suchspecialized multi-nozzle fused filament fabrication (FFF) printers maybe quite costly, as well as being so large and bulky as to not besufficiently portable.

In embodiments of the present invention, the thermoplastic filaments areprovided with adjacent portions, regions, sections, etc. (i.e.,hereafter referred to as “segments”) of the filament which includediffering features (e.g., differing material compositions) so that thatthe filament may be engineered and adapted for use in a fused filamentfabrication (FFF) printer, even and especially if that FFF printer hasonly one printing nozzle, as well as to allow and allow printing of anarticle comprising several materials which are different from eachother. These thermoplastic filaments comprise a plurality of segments,each segment comprising at least thermoplastic polymer, but which mayalso comprise other materials which may be substantially uniformlydispersed in the thermoplastic polymer matrix. In other words, each pairof adjacent segments of the filament have at least one different featurein terms of composition, appearance, functional properties, etc. Forexample, these differences in features may include one or more offollowing: (1) different structural materials, sacrificial (removable)materials, etc.; (2) materials of different color (e.g., differentcolorants), including materials which are different in terms ofopaqueness, transparency, translucency, fluorescence, etc.; (3)different additives, e.g., fillers, plasticizers, solvents, etc.,including different types and amounts of such additives; (4) materialshaving different functional properties, e.g., electrically conductivematerials, semiconductive materials, insulating materials, etc., such aselectroactive polymers, piezoelectric materials, etc.; (5) materialshaving different mechanical and physical properties, such as in terms ofmodulus, viscoelasticity, plasticity; magneticity, etc.; (6) materials,such as quantum dots, with impart different optical or spectroscopicproperties, including different refractive indices, fluorescenceproperties, etc.; (7) materials which are different in being infusedwith, having incorporated therein, etc., other two-dimensional (2D)materials such as graphene nanoplatelets, carbon or/and inorganicnanotubes, flakes of graphene-like materials such as molybdenum andtungsten disulfides flakes, boron nitride flakes, carbon black, carbonfibers, fullerenes, etc.; (8) materials having different thermalstability, chemical stability or solubility; (9) materials havingdifferent thermal conductivity; (10) materials having higher and loweratomic numbers (i.e., different Z numbers), higher or lower molecularweights, etc.; (11) materials with different permeability for gases,ions, liquids, etc.; etc. Segments of embodiments of the thermoplasticfilaments according to the present invention may have similar ordiffering lengths, may have physical properties which change graduallyor abruptly along or throughout the entire length of the filament, etc.

In addition, these segments are arranged in a specified order in thethermoplastic filament to provide a synchronized pattern of printingwhen the filament is printed with a fused filament fabrication (FFF)printer. In other words, embodiments of the thermoplastic filaments ofthe present invention are created with segments in a predetermined ordersuch that, when printed with a fused filament fabrication (FFF) printer,the fused filament fabrication (FFF) printer lays down a “road(s)” ofthe material in a synchronized pattern that, upon completion of theprinting, provides the printed three-dimensional (3D) article, device,component, object, structure, part, etc., which may have differentcolors throughout, may have embedded functionality, such as electricalcircuitry, heat sinks, sensors, other electronics, etc. Embodiments ofthe thermoplastic filaments according the present invention thus providesignificant processing flexibility, even with fused filament fabrication(FFF) printers having a single printing nozzle.

Besides processing flexibility, these thermoplastic filaments may alsoprovide a significantly enhanced ability to create reproducible numbersof the same printed article, device, component, object, structure, part,etc., due to consistent fabrication of the thermoplastic filament, or tovary the features of the printed article, device, component, object,structure, part, etc., by simply altering the composition of one or moresegments and the order those segments are arranged in, while still usingthe same fused filament fabrication (FFF) printer by simply altering theprogramming (e.g., a computer program file, such as computer assisteddrawing (CAD) program file, stereolithographic (STL) file, etc.)controlling that printer to be synchronized with the varied segments,order of segments, etc., of thermoplastic filament. Some of theembodiments of these thermoplastic filaments may allow for theproduction of three-dimensional (3D) printed fully orpartially-integrated circuitry. The flexibility and variability of theembodiments of the thermoplastic filaments of the present invention maycreate a compact fused filament fabrication (FFF) printer system whichmay print out a complete working devices, such as power sources,electronics, actuators, sensors, and mechanical components, biologicalmaterials, etc., in any geometry, shape, size, configuration,interconnection, etc., desired.

An example of an embodiment of thermoplastic filament according to thepresent invention (hereafter referred to for convenience only as“thermoplastic multi-segment filament”) which may be used with a fusedfilament fabrication (FFF) printer having a single printing nozzle isillustrated in FIG. 1 and indicated as 100. As shown in FIG. 1, filament100 comprises a plurality of segments, of which four are shown and areindicated as 104-1, 104-2, 104-3, and 104-4. Each of segments 104-1,104-2, 104-3, and 104-4 may have different features in terms ofcomposition, appearance, functional properties, etc., e.g., each ofthese four segments may be comprised of different materials, or onlyeach pair of adjacent segments may be comprised of different materials.For example, segments 104-1 and 104-3 may be comprised of the samematerial(s) (e.g., the same colorant, the same functional material,etc.), while segments 104-2 and 104-4 may be comprised of the samematerial(s) but which is different from the material(s) of whichsegments 104-1 and 104-3 are comprised (e.g., a different colorant, adifferent functional material, only thermoplastic polymer, with orwithout other additives such as filler, plasticizers, solvents, etc.).As shown with respect to segment 104-2, each segment has a body portionindicated, respectively, as 108-1, 108-2, 108-3, and 108-4, as well asrespective ends, boundaries, edges, etc., indicated respectively as112-1, 112-2, and 112-3 which define where adjacent segments begin andend. For example, 112-1 defines the end/boundary between adjacentsegments 104-1/104-2, 112-2 defines the end/boundary between adjacentsegments 104-2/104-3, and 112-3 defines the end/boundary betweenadjacent segments 104-3/104-4. As also illustrated in FIG. 1, segments104-1, 104-2, 104-3, and 104-4 may have different lengths or the samelength, the particular length of each segment being dictated by thematerials present in that segment, wherein the pattern of lay down of“roads” of material by the filament fabrication (FFF) printer isdetermined by where that segment is to be present in filament 100.

In some embodiments of the thermoplastic multi-segment filaments of thepresent invention, one of the adjacent segments comprises a polymermatrix without functional materials being present (e.g., to form thebody, case, container, etc., of the printed three-dimensional (3D)article, device, component, object, structure, part, etc.), while theother of the adjacent segments comprises a polymer matrix withfunctional materials being present. For example, filament segments 101-1and 101-3 may comprise a polymer matrix without functional materialsbeing present, while filament segments 101-2 and 101-4 comprise apolymer matrix but with functional materials being present (e.g.,two-dimensional (2D) materials such as graphene nanoplatelets, carbonor/and inorganic nanotubes, flakes of graphene-like materials such asmolybdenum and tungsten disulfides flakes, boron nitride flakes, carbonblack, carbon fibers, fullerenes, etc.). In other embodiments of thethermoplastic multi-segment filaments of the present invention, one ofthe adjacent segments may comprise a polymer matrix with structuralmaterials being present (e.g., carbon fibers, etc.), while the other ofthe adjacent segments comprises a polymer matrix with functionalmaterials being present which may form electronics, such as electroniccircuitry (e.g., graphene nanoplatelets, carbon or/and inorganicnanotubes flakes of graphene-like materials such as molybdenum andtungsten disulfides flakes, boron nitride flakes, carbon black, carbonfibers, fullerenes, etc.)

FFF Printing with FFF Printer Having Single Printer Head

Embodiments of the thermoplastic multi-segment filaments of the presentinvention permit fused filament fabrication (FFF) printing of adjacentfilament segments comprising different materials, even with fusedfilament fabrication (FFF) printers having a single printing head (i.e.,printing nozzle), as illustrated in FIG. 2. Referring to FIG. 2, thefused filament fabrication (FFF) printer is indicated generally as 200.Printer 200 includes a printing nozzle, indicated generally as 204,which may be moved horizontally back and forth and side-to-side (i.e.,in the X and Y directions), as well as vertically up and down (i.e., inthe Z direction), and which has an upper filament entry end, indicatedas 208, a lower extrusion orifice end, indicated as 212, and a main bodyportion, indicated as 216. Printing nozzle 204 has a generallycylindrically-shaped extrusion chamber, indicated as 220, for receivingthe filament (e.g., such as filament 100 illustrated in FIG. 1),indicated as 224, and which extends from upper end 208 to lower end 212.Provided in main body portion 216 is a pair of gears, indicated as 228-1and 228-2 which engage and advance filament 224 towards lower end 212.Filament 224 is shown as comprising a segment, indicated as 224-1 whichis shown entering extrusion chamber 220 at upper end 208, an adjacentsegment, indicated as 224-2, and a segment, indicated as 224-3 adjacentsegment 224-3 which is being extruded by printing nozzle 204. Alsoprovided in main body portion 216 near lower end 208 is a heater element(liquefier), indicated as 232, which heats and liquefies (softens)segment 224-3 of filament 224 so that segment 224-3 may be extrudedthrough the extrusion orifice (die), indicated as 236. The liquefied,softened segment 224-3 is shown FIG. 2 as being extruded throughextrusion orifice to form a “road” of material, indicated as 240, whichis deposited on a printing bed, indicated as 244. The deposited “road”of material 240 includes two segments, indicated as 240-1 and 240-2, aswell as a portion of segment 224-3, indicated as 240-3, which iscurrently exiting though extrusion orifice 236 and is about to bedeposited on printing bed 244.

As shown in FIG. 2, main body portion 216 of printing nozzle 204 mayalso be equipped with a sensor, indicated as 248. Sensor 248 may be usedto read and recognize the indicia (e.g., markings, bar codes, etc.) onfilament 224 which may provide information, data, etc., as tocharacteristics of filament 224, including what the composition is(i.e., what materials are present) in each of segment 224-1 through224-3 of filament 224, identifying the ends/boundaries of each ofsegment 224-1 through 224-3, what temperature, filament throughput rate,etc., may be required for operating liquefier 232 and gears 228-1/228-2,etc. Such indicia may be present on the starting segment (i.e., segment240-1) only of filament 224, may be present at various points alongfilament 224, etc.

As illustrated in FIG. 2, filament 224 may be pre-formed (e.g., likefilament 100 of FIG. 1) before being supplied to extrusion chamber 220.In other embodiments, filament 224 may be formed, for example, inanother extruder positioned in before printer 200 which then suppliesthe formed filament 224 to extrusion chamber 220. When another extruderis used, portions of material(s) corresponding to each segment offilament 224 may be supplied to the extruder in the appropriate(specified) order that the segment will appear in the finished filament224. This extruder then forms filament 224 with the plurality ofsegments in the specified order which may be permitted to solidifybefore being supplied into extrusion chamber 220, or which may besupplied to extrusion chamber 220 prior to complete solidification offilament 224 as long as printing nozzle 204 may extrude the partiallysolidified filament through extrusion orifice 236 to form “road” ofmaterial 240.

In some embodiments of the method of the present invention, the fusedfilament fabrication (FFF) printer, such as printer 200 illustrated inFIG. 2, may be operate in what is hereafter referred to as a “passiveprinting” mode. In a “passive printing” mode, the composition, length,order, etc., of the segments of filament 224 required to print thearticle, device, component, object, structure, part, etc., arepredetermined (e.g., filament 224 is already fabricated according toinstructions from a computer program file such as, a computer assisteddrawing (CAD) program file, stereolithographic (STL) file, etc., whichdescribes, for example, the composition, order, length and/orstarting/end point, etc., of each of the plurality of segments infilament 224, the computer program file being generated by a computerprogram based upon the structure of the article, device, component,object, structure, part, etc., to be printed by printer 200) in filament224. Filament 224 is then supplied to printer 200 with printing nozzle204 automatically printing the article, device, component, object,structure, part, etc., according to preset operating conditions in termsof temperature, throughput rate, etc., the lay down pattern from theprinting nozzle 204, etc. In other words, in a “passive printing” mode,printer 200 operates essentially in a preset manner, other than sensor248 determining the forward end of filament 224 is within extrusionchamber 220 and reading any indicia (e.g., marks) present on filament224 which indicate the temperature conditions for operating printingnozzle 204. In other words, filament 224 may be loaded into extrusionchamber 220 with printing nozzle 204 moving along in a predeterminedpath and pattern to lay down the “road” of material 240 to print thearticle, device, component, object, structure, part, etc. For example,the “road” of material 240 may be laid down in a continuous spiralpattern, in a continuous sinuous “snake-like” back and forth pattern, ina back and forth pattern that lays down a discontinuous series of“roads” of material, etc.

One such pattern for printing filament 224 is illustrated in FIG. 3 andis indicated generally as 300 which forms a “G” shape of one darkercolor, indicated as 304, in the background, indicated as 308, of adifferent lighter color. As illustrated in FIG. 3, printing nozzle 204is shown to be moving in a continuous sinuous “snake-like” back andforth pattern which lays down lengths of extruded filament material, twoadjacent lengths being indicated as 312-1 and 312-2. Background 308 isinitially formed from a relatively long segment of lighter colormaterial, indicated as 308-1. The “G” shape 304 is initially formed fromseveral shorter segments of darker colored material, two of which areindicated as 304-1 and 304-2, with a lighter colored segment, indicatedas 308-2, printed therebetween, i.e., the darker colored segments 304alternate with the lighter colored segments 308. The last segment ofdarker colored material, indicated as 304-3, is then followed by anotherlonger segment of lighter colored material, indicated as 308-3.Different color patterning as illustrated by FIG. 3 may be used to formmulti-colored three-dimensional (3D) printed articles which may providedecorated objects, elements of a design, ads, billboards, promotionmaterials, interactive posters, etc., including decorative coatingsapplied to the exterior of a printed article. Instead of differentcolored materials, segments 304 may comprise other materials, forexample, materials which fluoresce to illuminate the “G” shape, whilesegments 308 forming the background comprise an opaque material.

In some embodiments of the method of the present invention, the fusedfilament fabrication (FFF) printer, such as printer 200 illustrated inFIG. 2, may be operated instead in what is hereafter referred to an“active printing with feedback control” mode. When operated in an“active printing with feedback control” mode, filament 224 may beprovided with indicia (e.g., marks, bar codes, etc.) which identify thecharacteristics of the segments comprising filament 224, including, forexample, segment composition, segment length (which may include theposition of the ends of the segment), segment order, etc., as well aswhat type of article, device, component, object, structure, part, etc.,which may be printed from filament 224, the operating conditions forprinting nozzle 204 in terms of temperature, filament throughput rate,etc., the lay down pattern of printing nozzle 204, etc. When sensor 248reads the indicia on filament 224, the identifying characteristics offilament 224 (e.g., composition, length, order, etc., of the segmentscomprising filament 224) conveyed by that indicia (which may simplyrepresent a code, number, etc., readable by sensor 248 and recognizableby printer 200), printer 200, based upon what indicia is read by sensor248, may then electronically transmit instructions to printing nozzle204 (based upon a computer program file such as a computer assisteddrawing (CAD) program file, stereolithographic (STL) file, etc., whichhas the electronic data which includes at least the composition, order,and length of each of the plurality of segments required for printingfilament 224 linked to the indicia read by sensor 248) to control theoperation of printing nozzle 204 in fused filament fabrication (FFF)printing of the article, device, component, object, structure, part,etc., identified by the indicia read by sensor 248.

For example, the article, device, component, object, structure, part,etc., may require a filament 224 which comprises alternating segmentscomprising two different compositions, such as two compositionscomprising different colorants. From reading special marks on filament224, sensor 248 then determines the relevant characteristic of filament224, including the composition of the alternating segments, and thentransmits that information, data, etc., to the computer controlling theoperation of printing nozzle 204. Based on the information data, etc.,convey by those marks on filament 224, printer 200 determines thepositioning of the printing nozzle 204, including the pattern and thepath that the printing nozzle 204 moves in both horizontal and verticaldirections, the operating conditions of printing nozzle 204 in terms oftemperature, filament throughput rate, etc. Similar to the “passiveprinting” mode, when operating in the “active printing with feedbackcontrol” mode, printing nozzle 204 moves along the predetermined pathand pattern (e.g., as instructed by printer 200 based upon instructionsfrom the relevant computer program file such as a computer assisteddrawing (CAD) program file, stereolithographic (STL) file, etc.) to laydown a “road” of material to print the article, device, component,object, structure, part, etc.

Printing with Multiple Printing Nozzles

In some embodiments, the thermoplastic multi-segment filaments accordingto the present invention may be used in combination with otherconventional thermoplastic filaments. In such instances, a fusedfabrication filament (FFF) printer having two or more printing nozzlesmay be used. For example, in a fused fabrication filament (FFF) printerhaving two printing nozzles, one printing nozzle may be supplied with aconventional thermoplastic filament uniformly comprising onecomposition, while other printing nozzle may be supplied with anembodiment of a thermoplastic multi-segment filament according to thepresent invention. In one such embodiment, printing of a box with anRFID tag that identifies the contents of the box may require athermoplastic multi-segment filament according to the present inventionfor FFF printing of the RFID tag, while the main body portion of the boxmay be FFF printed with a conventional thermoplastic filament comprisingonly a polymer matrix, such as a acrylonitrile butadiene styrene (ABS)polymer.

Fabrication of Thermoplastic Multi-Segment Filament

Embodiments of the thermoplastic multi-segment filament according to thepresent invention may be fabricated, manufactured, etc., by a variety ofdifferent methods, such as the following:

Assembly from Segments Obtained from Other Filaments.

In one embodiment, the design of the article, device, component, object,structure, part, etc., to be printed may be analyzed to determine thecomposition, length, order, etc., of the segments required. A pluralityof segments having the appropriate composition, length, etc., may thenbe formed, each having a pair of spaced apart ends, by, for example,cutting, slicing severing, etc., such segments from two or morecontinuous filaments having the appropriate compositions in the correctslengths, assembling the formed segments in the correct (specified)order, and then joining, connecting, fusing, splicing, etc., together bymeans of light, heating, ultrasonic energy, laser energy, microwaveenergy, etc., to form the thermoplastic multi-segment filament having aplurality of segments in the correct (specified) order for printing ofthe article, device, component, object, structure, part, etc. with afused fabrication filament (FFF) printer. Alternatively, these segmentsarranged in the correct (specified) order may also be joined, connected,spliced, etc., together to form a continuous filament by using adhesive(glue), solvent, etc., to soften the segments at the ends thereof sothat the ends of adjacent segments adhere to form a continuous length offilament.

In one embodiment of the method for fabricating thermoplasticmulti-segment filament according to the present invention, a supply of afirst thermoplastic filament and a supply of a second thermoplasticfilament are provided, wherein the first thermoplastic filament has atleast one feature which is different from the second thermoplasticfilament (e.g., the first thermoplastic filament has a color differentfrom the second thermoplastic filament). A first set of segments, eachhaving a forward end and a trailing end spaced apart from the forwardend, is formed form the first thermoplastic filament, while a second setof segments, each also having a forward end and a trailing end spacedapart from the forward end, is formed from the second thermoplasticfilament by, for example, cutting, slicing severing, etc., suchsegments. Each segment of the first set of segments and each segment ofthe second set of segments is formed alternatively and sequentially suchthat each segment of the first set of segments is adjacent to a segmentof the second set of segments. For each of the adjacent segments, thetrailing end of one of the adjacent segments is the forward end of theother of the adjacent segments is aligned and while the ends are incontact, joined, connected, fused, spliced, etc., to by light, heating,ultrasonic energy, laser energy, microwave energy, etc., to form thethermoplastic multi-segment filament having a plurality of segments inthe correct (specified) order. Alternatively, trailing and forward endsof the adjacent segments may also be joined, connected, spliced, etc.,together to form a continuous filament by using adhesive (glue),solvent, etc., to soften the trailing and forward ends so that thesetrailing and forward ends of adjacent segments adhere to form thethermoplastic multi-segment filament.

In some embodiments, the segments of the thermoplastic multi-segmentfilament may be assembled prior to being supplied for fused fabricationfilament (FFF) printing (i.e., the filaments are preformed), or thesegments of the filament may be supplied and assembled during fusedfabrication filament (FFF) printing (i.e., the filament is assembled insitu). In one embodiment of filaments which are assembled in situ, adevice assembling the segments of the filament (hereafter referred to as“filament assembly device”) may be used in conjunction with the fusedfilament fabrication (FFF) printer. For example, a computer program mayanalyze the structure of a previously printed article that may becomprised of several different materials. This analyzed structure maythen be expressed as a computer assisted drawing (CAD) file, such as astereolithography (STL) file. This STL file may then be converted into aseries of commands (e.g., by using a programming language for numericalcontrol, such as G-code) for the operation of the FFF printer to printthe article, as well as a series of commands to the filament assemblydevice for how to assembly the segments of the filament in the correct(specified) order so that the FFF printer prints the article correctly.

An embodiment of a filament assembly device for fabricatingthermoplastic multi-segment filaments according to the present inventionwhich may be used to provide preformed filaments (such as such asfilament 100 shown in FIG. 1), or which may be used to assemble filamentsegments in situ in conjunction with a fused fabrication filament (FFF)printer is schematically illustrated in FIG. 4, and indicated generallyas 400. Device 400 includes a first filament supply component and asecond filament supply component in the form of, for example, a firstrotatable filament supply spool, indicated as 404-1 and a secondrotatable filament supply spool, indicated as 404-2. Spool 404-1supplies a first filament, indicated as 408, while spool 404-2 suppliesa second filament, indicated as 412. Filaments 408 and 412 each have atleast one feature which is different, for example, filament 408comprises different materials from those present in filament 412, has adifferent color from filament 412, etc. As shown in FIG. 4, filament 408is fed from spool 404-1 through first filament guide component,indicated generally as 414-1, having a first filament guide, indicatedas 416-1 attached to, secured to mounted on, etc., a first plate,indicated as 420-1, while filament 412 is fed from spool 404-2 through asecond filament guide component, indicated generally as 414-2, alsohaving a second filament guide, indicated as 416-1 attached to, securedto, mounted on, etc., a separate second plate, indicated as 420-1.Plates 420-1 and 420-2 may be moved reciprocally from side-to side, inthe directions indicated by double headed arrow 424, along a pair ofspaced apart support rails, indicated as 428-1 and 428-2, thus allowingeither filament 408 or filament 412 to be alternatively and sequentiallypositioned underneath a roller, indicated as 432. (Spools 404-1 and404-2 also move side-to side in the directions indicated by doubleheaded arrow 424 in synchronization, respectively, with the side-to-sidemovement of plates 420-1 and 420-2).

As shown in FIG. 4, filament 408 is currently positioned underneathroller 432. Roller 432 advances filament 408 in the direction indicatedby arrow 436 towards a first pair of rollers, indicated as upper roller440-1 and lower roller 440-2, the direction indicated by arrow 436 beingthe direction of advance of filament 408 which is substantiallyorthogonal to the direction(s) of reciprocal side-to side movement ofplates 420-1 and 420-2 defined by double headed arrow 424. After aspecified length of filament 408 has been advanced by roller 432, afilament cutter component in the form of, for example, a verticallyreciprocating knife, indicated as 444, which is positioned betweenroller 432 (and thus also spools 404-1/404-2) and rollers 440-1/440-2,and which moves downwardly (i.e., moves substantially orthogonalrelative to the direction of arrow 436 and substantially parallel to thedirection(s) of double headed arrow 424) in the direction indicated byarrow 448 to cut (slice) filament 408, to thus form a trailing end (notshown) in a filament segment, indicated as 408-1, from filament 408, anda forward end (not shown) in what will be the next filament segmentformed from filament 408. After filament 408 is sliced by cutting knife440 to form the trailing end of filament segment 408-1, plate 420-1 maybe moved sideways out from underneath roller 432, with plate 420-2 thenbeing moved sideways underneath roller 432 in sequence so that filament412 may be advanced by roller 432 toward rollers 440-1/440-2 andeventually cut into an appropriate length by reciprocating knife 444 toform the next filament segment from filament 412. In other words, thefilament segments (such as filament segment 408-1) are formed (i.e., bycutting with reciprocating knife 444) alternatively and sequentially sothat each filament segment formed from filament 408 is adjacent to afilament segment formed from filament 412.

As shown in FIG. 4, rollers 440-1/440-2 advance filament 408 (in thedirection indicated by arrow 436) towards a filament segment joiningsection (shown in sectional view), indicated generally as 448, having acentral horizontally extending generally cylindrically-shaped chamber,indicated as 452, for guiding filament 408 therethrough, and aligningthe forward end of filament segment 408-1 with the trailing end of aprior segment cut filament segment formed from filament 412, indicatedas 412-1. While the forward end of filament segment 408-1, and thetrailing end of a filament segment 412-1 are aligned and in contact, aheater element, indicated as 456, heats the forward end of filamentsegment 408-1 and the trailing end of filament segment 412-1 so as tojoin, splice, connect, fuse, etc., these two ends together to form acontinuous multi-segment filament, indicated as 460. Multi-segmentfilament 460 may then be advanced by a second pair of rollers, indicatedas upper roller 464-1 and lower roller 464-2 to either a take up spool(not shown), or directly to the fused filament fabrication (FFF)printer. (The rotational speed of rollers 440-1/440-2 and rollers464-1/464-2 is synchronized to avoid pulling apart the joined, spliced,connected, fused, etc., the forward end of filament 408 and the trailingend of segment 412-1.) Device 400 may also be controlled by a computerprogram to carry out the various operations of device 400, as previouslydescribed. In addition, while device 400 shows forming multi-segmentfilament 460 from two thermoplastic filaments (i.e., 408 and 412),device 400 may be altered by appropriate modification by those skilledin the art to accommodate forming multi-segment filament 460 from morethan two thermoplastic filaments.

Continuous Production by Extrusion.

In another embodiment, thermoplastic multi-segment filaments accordingto the present invention may be fabricated, manufactured, etc., byextrusion. The process of extruding the thermoplastic multi-segmentfilaments may be continuous, wherein different materials may be loadedinto, supplied to, etc., an extruder at different times during theextrusion process to form adjacent segments of the filament having atleast one feature which is different, for example different materialscompositions. Instead of loading or supplying different materials,various polymer additives may be loaded into/supplied to the extruder tomodify the properties of the polymer. For example, these additives maybe different colorants (e.g., pigments of various colors), graphenenanoplatelets, nanoplatelets of other two-dimensional (2D) materialssuch as molybdenum disulfide, boron nitride, carbon nanotubes,nanoparticles, etc. The materials may be supplied to the extruder in theappropriate order determined by the characteristics of the article,device, component, object, structure, part, etc., to be printed.

For precise and reliable fused filament fabrication (FFF) printing,embodiments of the thermoplastic multi-segment filaments may befabricated, manufactured, etc., with indicia (e.g., one or more marks,bar codes, etc.) indicating the relevant characteristics, etc., such assegment composition, segment length (which may include the position ofthe ends of the segment), segment order, etc., wherein the fusedfilament fabrication (FFF) printer has a device (e.g., sensor 248) forreading and recognizing what information, data, etc., is conveyed by theindicia for controlling the operation of the fused filament fabrication(FFF) printer for that thermoplastic multi-segment filament, includingthe composition, order and length of the segments comprising thethermoplastic multi-segment filament being marked, optimal processingparameters, such as the deposition temperature and the filamentthroughput rate for advancing the filament, the pattern and path ofmovement of the printing nozzle, etc. Such indicia may be in the form ofa marker which informs the printer of when each segment of the filamentstarts, such as segments having slightly different shapes, diameters,etc. Such markings may also be applied to the filament during theextrusion process. Alternatively, such marks may be applied, coated,painted, etc., onto the surface of the filament by using special coding,e.g., combinations of letters and numbers, bar codes, etc. In someembodiments, infusion of materials in the segments that provide anoptical response to visible light, polarized light, UV, IR, other typesof radiation, etc., may be used, including fluorescence detection.

Repeatable 3D Printing of Devices, Structures, Components, Parts.

In many cases, the same device, structure, component part, etc., may beused multiple times. For example, a circuit board may use a plurality ofidentical resistors and capacitors. Similarly, a power supply, batteryetc., may be used in many different devices. Embodiments of thethermoplastic multi-segment filaments according to the present inventionprovide the ability to repeatedly print such devices, structures,components, parts, etc., with a fused filament fabrication (FFF) printerby preparing a plurality of such filaments having the required specifiedsegments in the appropriate order.

Printing of Devices with Functional Elements Incorporated into a PolymerMatrix Body.

Fused filament fabrication (FFF) printing of thermoplastic multi-segmentfilaments according to the present invention may be combined with FFFprinting of conventional filaments. For example, a device may becomprised of a body made of polymer matrix, with one or more functionalelements, such as sensors, incorporated into that body. Each of thesensors may be comprised of two electrical leads and a strip of anenvironmentally sensitive material between the two leads, thatenvironmentally sensitive material sensitive being able to change itselectrical conductivity properties in response to changes in thesensor's environment, for example, changes in temperature, pressure,concentration of trace gases, etc. Such environmentally sensitivematerials may include one or more of: metal oxides such as copper,manganese oxides, etc., which change electrical conductivity propertiesin response to temperature; graphene, such functionalized graphene,etc., which change electrical conductivity properties in response tobeing exposed to various gases, vapors, etc., etc. Manufacturing ofthese devices may be accomplished with a fused filament fabrication(FFF) printer having two printing nozzles, one supplied with thefilament comprising a polymer matrix used to build the body of thedevice, the other printing nozzle being supplied with thermoplasticmulti-segment filaments according to the present invention to print thesensors. Examples of sensors which may benefit from this method mayinclude damage control sensors for wind turbine blades, capacitance“touch-sensitive” sensors, moisture and icing sensors, protein or otherbiosensors, etc.

Manufacturing Repeating Periodic Patterns in Articles.

Embodiments of thermoplastic multi-segment filaments according to thepresent invention may be used to manufacture article having repeatingperiodic patterns, e.g., a checkerboard pattern, articles printed byfused filament fabrication (FFF) printing. One advantage suchthermoplastic multi-segment filaments may provide in printing suchrepeating periodic patterns is increased speeds and throughput rates forpart manufacturing when compared to manufacturing the same pattern withthree-dimensional (3D) printers equipped with multiple printing heads,each loaded with a certain material. These repeating periodic patternsmay be, for example, a variety of meta-materials includingnano-scaffolds, photonic crystals, optical gratings, materials withnegative index of refraction, etc. In this method, the pieces ofdifferent materials may interchange with each other in a periodicmanner.

Printing Heat Sinks for Thermal Management.

Heat sinks may be used to protect important elements from overheating,and often have complex shapes for seamless integration. In some cases,anisotropic heat transfer may be beneficial. In one embodiment, thesethermoplastic multi-segment filaments may be used to form heat guides bycombining materials with both higher and lower thermal conductivities,such as by creating a continuous extended structure comprising of amaterial having a higher thermal conductivity surrounded by anothermaterial having lower thermal conductivity such that excessive heat maypass along this structure. Such heat guides may be incorporated into thethree-dimensional (3D) article directly by interchanging the materialsof higher and lower thermal conductivity during the printing of thearticle. This application may target industries including, but notlimited to, semiconductor equipment, housing for light sources, devicespackaging, and equipment boxes.

Three-Dimensional (3D) Printed Batteries.

A battery may be comprised of the set of parts that include currentcollectors made of electrically conductive material, a cathode, anelectrolyte (to provide ionic conductivity), and an anode. Each of theseparts may require different materials. The materials for each of theseparts may be formulated as thermoplastic composites. These thermoplasticcomposites may be formed into separate filaments which are cut intosegments and spliced together (for example, by device 400 of FIG. 4)into a multi-segmented thermoplastic filament. By combining the filamentsegments the form each of the parts into a multi-segmented thermoplasticfilament, a functional battery may be fabricated with suchmulti-segmented thermoplastic filament using a FFF printer equipped witha single printing nozzle.

Security Devices and Antennas.

Conductive traces may be used as antennas and RFID tags. Such tags maybe embedded in the interior of the device and are not visible to theuser.

RF, Anti-Static, and EMI Shielding.

Protection of sensitive equipment may be implemented if a conductiveenvelope is embedded in a 3D printed object.

Elements with Embedded Heaters.

Thermoplastic multi-segment filaments may be used provide embeddedheaters. Examples of such applications may include heated car seats,deicers, heated tiles, walls or floor units with heaters, etc. Displaysthat change color with heating (e.g., thermocromes) may also benefitfrom using such thermoplastic multi-segment filaments in theirfabrication.

Authenticity Marks.

Thermoplastic multi-segment filaments may have regions which may lookidentical, but which have special indicia (e.g., authenticity marks,signatures, etc.) which may be revealed, recognized, etc., if examinedwith specialized equipment (e.g., fluorescent scanners). For example,some regions or segments of thermoplastic multi-segment filaments mayhave fluorescent marks, isotope marks, etc.

Shock Absorbers, Materials with Anisotropic Mechanical Properties

Thermoplastic multi-segment filaments may suitable for fused fabricationfilament (FFF) printing of wearable electronics, armor, (includingpersonalized armor), helmets (including with embedded electronics),structures (e.g., cellular structures) used for protection fromexplosion, falling construction parts, earthquakes, etc.

Medical Applications.

With thermoplastic multi-segment filaments, one may fused fabricationfilament (FFF) print scaffolds for the growth of different types oftissue, artificial bones and limbs, etc. With thermoplasticmulti-segment filaments, anti-bacterial layers may be added by fusedfabrication filament (FFF) printing to casts or implants.

Internal Wiring, Device Cases, Parts for Robots, Unmanned Vehicles

Embodiments of thermoplastic multi-segment filaments according to thepresent invention may be useful for a broad range of applications toembed internal wiring, sensors, light guides, etc., in a bulk part or acase, including, for example, in robotic devices, unmanned submarines,spacecraft, aircraft (e.g., unmanned aircraft such as drones, etc.),etc.

Radiation Protection.

Layers of material with high Z may be added around sensitive parts forradiation protection. Applications include vehicle protection, gasmasks, vests, shielding of radiation-sensitive robotic parts.

Filaments with Gradually Changing Features.

The features of the thermoplastic multi-segment filaments according tothe present invention may gradually change along the length of thefilament.

Optical Lens.

The segments of the thermoplastic multi-segment filaments according tothe present invention may be made of an optically transparent material,with the refraction index gradually increasing along the length of thefilament. Such filaments may be used for manufacturing optical lenses.For example, the fused filament fabrication (printer) may be originallypositioned over the center of the lens, and may then be moved along anoutwardly the spiraling path to distribute the “road” of material.

This application may incorporate material which is subject to copyrightprotection. The copyright owner has no objection to the facsimilereproduction by anyone of this application or any portion of thisdisclosure, as it appears in the Patent and Trademark Officepatent/patent application file or records, for the limited purposesrequired by law, but otherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the scope of thepresent invention should not be limited by any of the above describedexemplary embodiments.

In addition, it should also be understood that any figures in thedrawings that highlight any functionality and/or advantages, arepresented herein for illustrative purposes only. The disclosedarchitecture is sufficiently flexible and configurable, such that it maybe utilized in ways other than those that may be shown. For example, thesteps listed in any flowchart may be re-ordered or only optionally usedin some embodiments.

Further, the purpose of the Abstract of the Disclosure in thisapplication is to enable the U.S. Patent and Trademark Office, as wellas the public generally, including any scientists, engineers andpractitioners in the art who are not familiar with patent or other legalterms or phraseology, to determine quickly from a cursory inspection thenature and essence of the technical disclosure of the application.Accordingly, while the Abstract of the Disclosure may be used to provideenablement for the following claims, it is not intended to be limitingas to the scope of those claims in any way.

Finally, it is the applicants' intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. §112, paragraph 6. Claims that do not expressly include thephrase “means for” or “step for” are not to be interpreted as beingwithin the purview of 35 U.S.C. §112, paragraph 6.

1. An article comprising a thermoplastic filament adapted for a fusedfilament fabrication (FFF) printer, the filament comprising: a pluralityof segments, each of the segments comprising a thermoplastic polymer;each pair of adjacent segments having at least one different feature;wherein the segments are arranged in a specified order in the filamentto provide a synchronized pattern of printing when the filament isprinted with a fused filament fabrication (FFF) printer.
 2. The articleof claim 1, wherein the at least one different feature is one or moreof: a difference of composition in the adjacent segments; a differenceof appearance in the adjacent segments; or a difference of functionalproperties in the adjacent segments.
 3. The article of claim 2, whereinthe differences in composition are one or more of: differences inmaterials, compounds, or substances present in the adjacent segments; ordifferences in amounts of the materials, compounds, or substancespresent in the adjacent segments.
 4. The article of claim 2, wherein thedifferences in appearance are one or more of: differences in color,shape, opacity, transparency, translucency, or fluorescence of theadjacent segments.
 5. The article of claim 2, wherein the differences infunctional properties are one or more of: differences in electricalconductivity, thermal conductivity, mechanical strength,viscoelasticity, solubility, or magnetic susceptibility of the adjacentsegments.
 6. The article of claim 2, wherein the at least one differentfeature is as difference in color of the adjacent segments.
 7. Thearticle of claim 2, wherein one of the adjacent segments comprises apolymer matrix without functional materials being present, and whereinthe other of the adjacent segments comprises a polymer matrix withfunctional materials being present.
 8. The article of claim 7, whereinthe functional materials can form electronics.
 9. The article of claim8, wherein the functional materials are one or more of: graphenenanoplatelets; carbon nanotubes; inorganic nanotubes; molybdenumdisulfide flakes; tungsten disulfides flakes; boron nitride flakes;carbon black; carbon fibers; or fullerenes.
 10. The article of claim 2,wherein one of the adjacent segments comprises a polymer matrixstructural materials being present, and wherein the other of theadjacent segments comprises a polymer matrix with functional materialsbeing present which can form electronics.
 11. The article of claim 1,wherein the thermoplastic filament is provided with indicia whichidentify one or more of: segment composition; segment length; or segmentorder.
 12. The article of claim 11, wherein the indicia identify thesegment composition, segment length, and segment order of thethermoplastic filament.
 13. The article of claim 12, wherein the indiciacomprise one or more marks on the thermoplastic filament.
 14. Thearticle of claim 1, wherein the thermoplastic polymer is one or more of:acrylonitrile-butadiene-styrene polymers; or polyethylene oxide (PEO)polymers.
 15. The article of claim 1, wherein the thermoplastic polymeris water-soluble.
 16. A method for printing a three-dimensional (3D)article, which comprises the following steps of: (a) providing athermoplastic filament adapted for a fused filament fabrication (FFF)printer, the filament comprising: a plurality of segments, each of thesegments comprising a thermoplastic polymer; each pair of adjacentsegments having at least one different feature; wherein the segments arearranged in a specified order in the filament; and (b) printing thefilament of step (a) with a fused filament fabrication (FFF) printer toform the three-dimensional (3D) article, wherein the fused filamentfabrication (FFF) printer carries out a pattern of printing synchronizedwith the order of the segments in the filament.
 17. The method of claim16, wherein step (b) is carried out with a fused filament fabrication(FFF) printer having only one printer nozzle.
 18. The method of claim17, wherein step (b) comprises operating the fused filament fabrication(FFF) printer according to preset conditions to print the article. 19.The method of claim 17, wherein the filament of step (a) is providedwith indicia which identifies characteristics of the segments in termsof at least segment composition, segment length, and segment order,wherein the fused filament fabrication (FFF) printer of step (b) has asensor which can read the indicia, and wherein the fused filamentfabrication (FFF) printer carries out step (b) in response to thecharacteristics read by the sensor.
 20. The method of claim 16, whereinstep (b) is with a fused filament fabrication (FFF) printer having twoor more printer nozzles.
 21. The method of claim 16, which comprises thefurther step (c) of: forming in an extruder the filament of step (a)from a plurality of segments arranged in the specified order.
 22. Themethod of claim 16, wherein step (a) includes the steps of: (d) by usinga computer program, determining electronic data including at least thecomposition, order, and length of each of the plurality of segmentsrequired for printing the filament of step (a) with a fused filamentfabrication (FFF) printer to form the three-dimensional (3D) article;and (e) generating a computer program file containing the determinedelectronic data of step (d), and wherein step (b) is carried out byprinting the filament of step (a) to form the three-dimensional (3D)article based upon the computer program file generated in step (e). 23.The method of claim 22, wherein the filament of step (a) is providedwith indicia which identifies characteristics of the segments in termsof at least segment composition, segment length, and segment order,wherein the fused filament fabrication (FFF) printer of step (b) has asensor which can read the indicia, and wherein the fused filamentfabrication (FFF) printer carries out step (b) in response to theindicia read by the sensor based upon the computer program filegenerated in step (e) which is linked to the indicia.
 24. The method ofclaim 16, wherein the at least one different feature is one or more of:differences in materials, compounds, or substances present in theadjacent segments of step (a); or differences in amounts of thematerials, compounds, or substances present in the adjacent segments ofstep (a).
 25. The method of claim 16, wherein the at least one differentfeature is one or more of: differences in color, shape, opacity,transparency, translucency, or fluorescence of the adjacent segments ofstep (a).
 26. The method of claim 25, wherein the at least onedifference is a difference in color of the adjacent segments of step(a).
 27. The method of claim 16, wherein the at least one differentfeature is one or more of: differences in electrical conductivity,thermal conductivity, mechanical strength, viscoelasticity, solubility,or magnetic susceptibility of the adjacent segments of step (a).
 28. Amethod for preparing a thermoplastic filament adapted for a fusedfilament fabrication (FFF) printer, which comprises the following stepsof: (a) providing a plurality of segments, each of the segmentscomprising a thermoplastic polymer and having a pair of spaced apartends, the segments being arranged in a specified order such thatadjacent segments have at least one different feature; and (b) joiningthe ends of the adjacent segments of step (a) to form a thermoplasticfilament having a plurality of segments which provides a synchronizedpattern of printing when the filament is printed with a fused filamentfabrication (FFF) printer.
 29. The method of claim 28, wherein step (a)is carried out by forming each of the plurality of segments from asupply of a first thermoplastic filament or a second thermoplasticfilament, wherein the first thermoplastic filament has at least onefeature which is different from the second thermoplastic filament. 30.The method of claim 29, wherein the first thermoplastic filament of step(a) is different in color from the second thermoplastic filament of step(a).
 31. The method of claim 29, wherein step (a) is carried out bycutting the first thermoplastic filament to form a first set of filamentsegments, and by cutting the second thermoplastic filament to form asecond set of filament segments, each of the filament segment of thefirst and second set having a forward end and a trailing end spacedapart from the forward end.
 32. The method of claim 31, wherein eachfilament segment of the first set and each filament segment of thesecond set are formed alternatively and sequentially in step (a) suchthat each filament segment of the first set is adjacent to a filamentsegment of the second set.
 33. The method claim 32, wherein step (b) iscarried out by aligning the trailing end of one segment of the adjacentsegments with the trailing end of the other of the adjacent segments,and while the trailing end and the forward end are in contact, joined toform the thermoplastic filament having a plurality of segments.
 34. Themethod of claim 33, wherein the trailing and forward ends are joined instep (b) by heating the trailing and forward ends.
 35. The method ofclaim 33, wherein the trailing and forward ends are joined in step (b)by applying adhesive or solvent to the trailing and forward ends.
 36. Adevice for fabricating a continuous thermoplastic filament having aplurality of segments, which comprises: a first filament supplycomponent for supplying a first thermoplastic filament; a secondfilament supply component for supplying a second thermoplastic filament;a filament cutting component for cutting each of the first and secondfilament into segments, each of the segments having a forward end andtrailing end spaced apart from the forward end; a first filament guidecomponent for guiding the first filament into position to be cut by thefilament cutting component; a second filament guide component forguiding the second filament into position to be cut by the filamentcutting component; a filament segment joining section positioned afterthe filament cutting component, the filament joining section having: achamber for guiding and aligning the forward end of one segment of thefirst and second filaments into contact with the trailing end of theother segment of the first and second filaments; and a heater elementfor heating and joining the trailing end to the forward end when incontact to form a continuous thermoplastic filament having a pluralityof segments; wherein the first and second filament guide components aremovable so as to alternatively and sequentially permit the first andsecond filaments to be cut by the filament cutting component.
 37. Thedevice of claim 36, wherein the first filament supply component is afirst rotatable filament supply spool, and wherein first filament supplycomponent is a first rotatable filament supply spool.
 38. The device ofclaim 36, wherein the first and second filaments are alternatively andsequentially advanced in a first direction towards the filament segmentjoining section, and wherein the a first filament guide component andthe second filament guide component are reciprocally movable in a seconddirection which is substantially orthogonal to the first direction sothat the first and second filaments can be alternatively andsequentially advanced in the first direction.
 39. The device of claim38, wherein the first filament guide component comprises a firstreciprocally movable plate and a first filament guide mounted on thefirst reciprocally movable plate, and wherein the second filament guidecomponent comprises a second reciprocally movable plate and a secondfilament guide mounted on the second reciprocally movable plate.
 40. Thedevice of claim 38, wherein the filament cutting component comprisesvertically reciprocating knife which moves substantially orthogonalrelative to the first direction and substantially parallel relative tothe second direction.
 41. The device of claim 38, wherein the chamber isgenerally cylindrical and extends generally horizontally through thefilament section joining section.